Elden Ring: Where to find the Ronin armor set

You'll come across an NPC named Yura on the quest for Bloody Fingers in the Lands Between. After defeating him, you'll be rewarded with several good weapons and Ashes of War, and if you follow him to the Mountaintops of the Giants, you'll be rewarded with the Ronin armor set.

You first meet Yura in Limgrave, as he assists Bloody Finger Nerijus in defeating him and receiving the Reduvia dagger. Yura also warns against fighting Agheel, Limrave's dragon, even though doing so leads to Dragon Communion. He'll be fighting the Ravenmount Assassin Bloody Finger in Liurnia of the Lakes next. The Raptor of the Mists Ash of War is your reward.

In the Altus Plateau, you meet Yura a third time at the Second Church of Marika, where he is dying. The Nagakiba katana is on his body, and you get Eleonora's Poleblade if you beat the Bloody Finger who spawns at the chapel. Shabriri, a student of the Three Fingers, the Frenzied Flame, and seeker of Lord of Chaos, takes over Yura's body for reasons that are never revealed.

You'll run and meet him near the Zamor Ruins Site of Grace early in your journey through the Mountaintops of the Giants. There, he proposes abandoning your ambition to become Elden Lord in favor of succumbing to the flames of rage. You do not need to do so in order to obtain Yura's armor set. You only need to kill Shabriri.

When Shabriri uses his Frenzy spells, hit him three times to make him hostile, and then keeps him far away. Shabriri doesn't have a lot of HP and can only recover once, so as long as you don't have the Madness condition, you shouldn't have too much trouble defeating him. Shortly after Shabriri's body vanishes into mist, you acquire the Ronin armor set.